Process for the production of cyanogen chloride

ABSTRACT

1. A PROCESS FOR THE PRODUCTION OF CYANOGEN CHLORIDE CONSISTING ESSENTIALLY OF REACTING (1) HYDROGEN CYANIDE WITH (2) AQUEOUS HYDROCHLORIC ACID AND (3) HYDROGEN PEROXIDE IN THE PRESENCE OF EITHER (A) A WATER SOLUBLE CUPRIC SALT AS A CATALYST IN AN AMOUNT OF AT LEAST 0.05 MOLE PER LITER OF SOLUTION OR (B) A WATER SOLUBLE CUPRIC SALT IN AN AMOUNT OF AT LEAST 0.05 MOLE PER LITER OF SOLUTION TOGETHER WITH A WATER SOLUBLE FERRIC SALT AS AN ACTIVATOR IN AN AMOUNT OF AT LEAST 0.05 MOLE PER LITER OF SOLUTION.

PROCESS FOR THE PRODUCTION OF CYANOGEN CHLORIDE Filed June 20, 1972 J.HEILOS ET AL Oct. 8, 1974 3 Sheets-Sheet 1 ew. 9c u Nu W Oct. 8, 1974 J,HEILOS E'TAL PROCESS FOR THE PRODUCTION OF CYANOGEN CHLORIDE 3 Sheets--Shee t 2 Filed June 20, 1972 Q a R w Rwv nun nun Q H A Z WQ "I," IIIIHHQM N. QM l! *0 W. I L "H" IHH" F ww# \QN PROCESS FOR THE PRODUCTION OFCYANOGEN CHLORIDE Filed June 20, 1972 Oct. 8, 1974 HE|LQ$ ETAL 3Sheets-Shed 5 United States Patent 3,840,648 PROCESS FOR THE PRODUCTIONOF CYANOGEN CHLORIDE Johannes Heilos, Seligenstadt, Werner Heimberger,Hanau, Theodor Lussling, Grossauheim, and Wolfgang Weigert, Offenbach,Germany, assignors to Deutsche Goldund Silher-Scheideanstalt vormalsRoessler, Frankfurt am Main, Germany Continuation-impart of abandonedapplication Ser. No. 153,467, June 2, 1971. This application June 20,1972, Ser. No. 264,455 Claims priority, application Germany, June 24,1971, P 21 31 383.7 Int. Cl. (101]) 21/00, 31/00; C01c 3/00 U.S. Cl.423-383 20 Claims ABSTRACT OF THE DISCLOSURE Cyanogen chloride isprepared from hydrogen cyanide, hydrogen chloride and hydrogen peroxidein the presence of cupric salts, preferably also in the presence offerric salts. Preferably the process is carried out continuously.

This application is a continuation-in-part of application 153,467 filedJune 2, 1971, now abandoned.

It is known to produce cyanogen chloride from hydrogen cyanide andchlorine. The reaction can take place according to equation I in the gasphase (Chem. Abst., Vol. 15/[192l], page 2593) or in aqueous solution(Heuser, U.S. Pat. 1,588,731 and German Pat. 827,358 and correspondingHuemer, U.S. Pat. 2,672,398). The hydrogen chloride formed in equimolaramounts is separated from the cyanogen chloride in various ways. Forexample, in working in aqueous phase, the separation of the hydrogenchloride as aqueous hydrochloric acid is relatively simple, since thecyanogen chloride is distilled therefrom as a gas. Similarly, theseparation of the gaseous mixture takes place during the reaction in thegas phase by subsequent water washes.

The concentration of the aqueous solution of hydrogen chloride formed,however, in both cases can be permitted to reach at most weight percentand the solution must be continuously hydroextracted to avoidsaponification of the cyanogen chloride gas.

Another type of separation involves the selective dissolution of thecyanogen chloride from the resulting gas mixture in the working up ofthe gas phase. Here there is first removed the hydrogen chloride as agas from the solution and subsequently follows the desorption of thecyanogen chloride at higher temperatures.

Although the last named method through the recovery of gaseous hydrogenchloride, which can then be further worked up, is more important thanthe other methods, it has the disadvantage that considerabledisturbances can occur through the trimerization of the cyanogenchloride under the named conditions.

Entirely apart from the expense for the separation of the hydrogenchloride formed until now, a part of the reaction partners is alwayslost through formation of this by-product.

It has now been found that the reaction between chlorine and hydrogencyanide can be so guided that cyanogen chloride is formed practicallyquantitatively if the chlorine is provided in situ to the hydrogencyanide, namely by reaction of hydrogen chloride or aqueous hydrochloricacid and hydrogen peroxide in the presence of copper salts, in a givencase with the additional presence of ferric salts. Preferably thereaction is carried out in continuous fashion.

3,840,648 Patented Oct. 8, 1974 In these processes there is no hydrogenchloride as byproduct, but the applied hydrogen chloride or the appliedhydrochloric acid is converted quantitatively to cyanogen chloride.

As aqueous hydrochloric acid solution there can be used solutions havinga concentration from 3 weight percent to the constant boiling acid (36weight percent), 10 weight percent hydrochloric acid also is verysuitable. Furthermore, iron containing waste hydrochloric acid can beemployed. As hydrogen cyanide, there can be used either the gaseous orliquid form, in a given case there can be used aqueous solutions ofhydrogen cyanide such as the socalled waste acid from the production ofacrylonitrile, for example. The hydrogen cyanide can be of 5 to weightpercent in the aqueous solution.

Hydrogen peroxide can be added as a 10-70 weight percent aqueoussolution, preferably as a 35 weight percent solution.

The hydrogen chloride, hydrogen cyanide and hydrogen peroxide are usedin equivalent amounts, i.e., in equirnolar amounts. An excess of any ofthe reactants is not preferred. There can be used the following moleratios:

Moles Hydrogen chloride 0.9 to 1.1 Hydrogen cyanide -a 0.9 to 1.0Hydrogen peroxide 0.9 to 1.1

The in situ formation of the chlorine takes place in the presence ofcupric salts, in a given case activated with ferric salts. As cupricsalts there can be added for example cupric chloride, cupric bromide,cupric nitrate, cupric cyanide and cupric sulfate. As ferric salts therecan be used the corresponding compounds such as ferric chloride, ferricbromide, ferric nitrate and ferric sulfate.

The cupric salts can be used in an amount of from 0.05 mole/liter ofreaction solution up to the saturation point in the reaction solution.These proportions are also true for the ferric salts, i.e. 0.05 mole/l.of reaction solution to the saturation point. The total amount of thesalts also lies in the range of 0.1 mole per liter of reaction solutionup to their saturation in the reaction solution. Preferably cupricchloride and ferric chloride are used together, namely in a total amountof 0.5 mole/l. of reaction solution.

The reaction occurs most advantageously at temperatures of 15-65 C. andcan even be from 0 to C., although the temperature is not the essence ofthe invention. A temperature of 50 C. is preferred.

It is suitable to premix the aqueous catalyst solution of cupric salt ina given case together with the ferric salt, with a part of the hydrogenchloride and to introduce into this mixture the other reaction partnersand the rest of the hydrogen chloride or the rest of the hydrochloricacid. Hydrogen cyanide preferably should only be introduced into thecomposition as it is consumed.

The process of the invention likewise is also useful to change thehydrochloric acid formed as a by-product in both of the former processesby reaction of hydrogen cyanide and chlorine into cyanogen chloride byaddition of hydrogen peroxide in the presence of the cupric saltcatalyst solution, after hydrochloric acid is formed in a given casealso containing ferric salts. In this connection, the reaction partnerschlorine and hydrogen cyanide likewise can also be added together fromthe beginning with the hydrogen peroxide and the aqueous cupric saltcatalyst solution (with or without the ferric salt). In this case, thehydrogen peroxide does not react with the chlorine present but only withthe hydrogen chloride formed during the reaction.

The speed of reaction is so great that no difficulties are encounteredin an industrial carrying out of the process.

The yield of cyanogen chloride amounts to over 95% of theory on athroughput of 80% based on the hydrogen cyanide added.

Unless otherwise indicated, all parts and percentages are by weight.

FIGS. 1, 2 and 3 of the drawings are schematic diagrams illustratingthree 'difierent Ways of carrying out the process continuously.

In the drawings like numbers refer to like parts.

The process will be further explained in connection with the followingexamples.

EXAMPLE 1 In a 250 ml. round bottomed flask equipped with stirrer,thermometer, reflux condenser and a feed immersion tube, there weredissolved in 100.0 grams of water, 17.0 grams of CuCl .2H O (0.1 mole)and 27.0

grams of FeCl .6H O (0.1 mole) and there were added with vigorousstirring 24.3 ml. of hydrocyanic acid and 50 ml. of concentratedhydrochloric acid. Inside of one hour there were now added 100 grams ofaqueous hydrogen peroxide and the temperature allowed to rise from C. to65 C. The optimum reaction temperature was at 65 C. The crude gascontained by gas chromatographic analysis:

Percent Cyanogen chloride 64 Dicyanogen 2 Oxygen 10 Hydrogen cyanide 24Considering the recycling of the hydrogen cyanide the cyanogen chlorideamounted to a yield of'95% of theory with a throughput yield of 71%,both calculated on the amount of hydrocyanic acid added.

EXAMPLE 2 Percent Cyanogen chloride 83 Hydrogen cyanide 5 Oxygen 12Since no dicyanogen is formed and the hydrogen cyanide can be recycled,there is obtained a yield of almost 100% of theory and a throughputyield of 94.4%, both calculated on the hydrocyanic acid added.

EXAMPLE 3 In the apparatus described in example 1, which was furtherprovided with an inlet tube for chlorine gas, there were dissolved in100 ml. of water, 17.0 grams (0.1 mole) of CuCl .2H O and 27.0 grams(0.1 mole) of FeCl .6H O.

According to the following equation:

there were added with strong stirring 40.5 ml. (equal to 27.0 grams or1.0 mole) of liquid hydrocyanic acid and 51 ml. of 30% (equal to 17.0grams of 100% or 0.5 mole) of aqueous hydrogen peroxide, as well as 36.0grams Cir 4 (0.5 mole) of chlorine gas within minutes while the reactiontemperature was held at 65 C. The crude gas had the following analysisby gas chromatography:

The amount of the condensed crude gases amounted to 60.1 grams whichcorresponds to a yield of 90.9% of theory of cyanogen chloride.

EXAMPLE 4 There were added to the apparatus described in example 3, 17.0grams (0.1 mole) of CuCl .2H O dissolved in ml. of water and 50 ml. ofconcentrated hydrochloric acid. Under strong stirring there were thenadded 40.5 ml. (equal to 27.0 grams or 1.0 mole) of liquid hydrocyanicacid and 51 ml. of 30% (equal to 17.0 grams of 100% or 0.5 mole) aqueoushydrogen peroxide solution, as well as 36.0 grams (0.5 mole) of chlorinegas within 90 minutes while the reaction temperature was held at 65 C.

The crude gas had the following composition by gas chromatographicanalysis:

There were obtained 60.8 grams of condensed crude gas which correspondsto a yield of cyanogen chloride of 93.0% of theory based on the hydrogencyanide added.

In the continuous carrying out of the process of the invention it ispropitious to remove from the cycle the water brought in with thehydrogen peroxide and the hydrochloric acid as well as that formed inthe reaction.

This can be provided for first by distilling off of the catalystsolution introduced into the cycle and the catalyslt solution is therebyagain concentrated to its initial va ue.

Besides it is also possible after removal of the cyanogen chloride fromthe reaction mixture to separate the cupric or ferric ions from thewaste water by precipitation with alkali or alkaline earth carbonates(eg, sodium carbonate, potassium carbonate, calcium carbonate, magnesiumcarbonate) as basic copper or iron carbonate and to dissolve theprecipitate with mineral acids, e.g. hydrochloric acid, hydrobromicacid, sulfuric acid and nitric acid. The dissolved salt is then returnedto the cycle. Especially suitable for the precipitation is calciumcarbonate. The preferred acids are hydrochloric acid and sulfuric acid.The corresponding cupric or ferric salts are then, as stated, againreturned to the inserted catalyst solution.

Instead of direct reaction of hydrogen cyanide and hydrogen peroxidewith hydrochloric acid, it is also possible to form the hydrochloricacid in the reaction solution itself by reaction of chlorine withhydrogen cyanide.

According to equation I cyanogen chloride and hydrochloric acid areformed whereupon the hydrochloric acid after removal of the cyanogenchloride in the usual manner is reacted with hydrogen peroxide accordingto equation II The reaction takes place according to equation III, thatis according to the sum of equations I and II.

2HCN+Cl +H O 2ClCN+2H O,

by dividing in half III corresponds to I-ICN+ /2 Cl /2H O ClCN+H O.

The advantage of operating in the manner just described is that thehydrochloric acid formed according to equation I cannot attain a highconcentration in the reaction solution because it is immediately reactedoil? and thereby the saponification of the hydrogen cyanide is reducedto a minimum.

EXAMPLE 5 In the apparatus of FIG. 1 which operated in a con- ,tinuousmanner, a solution of 400 grams of CSO -5H O (1.6 moles) and 72.2 gramsof FeSO -7H O' (0.26 mole) in 40 kg. of water in reactor 1 by quickmixing by means of a pump (not shown) was led into the cycle overconduit 10.

Acording to the following equation:

approximately equimolar amounts of hydrogen peroxide, hydrochloric andhydrocyanic acid were introduced from the side into the reactionsolution through conduits 12, 14 and 16. The reaction temperature washeld to about 50 C. by cooling with the help of heat exchanger 5. Fromthe top of the reactor 1 the crude cyanogen chloride gas reached washingcolumn 18 over conduit 20. In the washing column the cyanogen chloridewas freed of an about 2% hydrocyanic acid constituent by counter currentwashing with chlorine containing water (by introduction of water overconduit 22 and chlorine over conduit 24). The cyanogen chloride gasleaving the washing column by conduit 26 still contains about 5 weightpercent of oxygen and carbon dioxide. The chlorine containing chieflyhydrochloric acid containing water leaves column 18 at the bottomthrough conduit 28 and 95% is returned as wash water by way of conduit30 into column 18 while the remainder is led back into reactor 1 by Wayof conduit 32 with fresh hydrochloric acid from conduit 14. Theseadditions are caused by the trifling decomposition of the hydrogenperoxide and the oxidative saponification of hydrocyanic acid.

To continuously eliminate the water brought in with the hydrogenperoxide solution and the aqueous hydrochloric acid and formed duringthe reaction (see the equation) the reaction solution is led by way ofconduit 34 into the distillation column 2 which was heated by heatexchanger 6. The reaction solution was freed here from the dissolvedcyanogen chloride and still unreacted hydrocyanic acid. The 011 gaspasses to conduit 36 which discharges into conduit 20 and then to thewashing column 18. By distilling off water, the steam passes by way ofconduit 38 into the condenser 4, the catalyst solution was concentrated.The concentrated catalyst solution was again returned by way of conduit40 to the reactor 1. In this apparatus (reactor 1) per hour there werereacted 0.932 kg. of hydrocyanic acid (34.6 moles) with 4.075 kg. of 31%aqueous hydrochloric acid (34.6 moles) and 3.735 kg. of 35% aqueoushydrogen peroxide solution (38.45 moles) to form 1.915 kg. of cyanogenchloride, i.e. about 90% of theory (2.13 kg.) calculated on the HCN.

Per hours about 6-7 kg. of water were distilled 01f via conduit 38.

EXAMPLE 6 In the apparatus of FIG. 2 which operated in a continuousmanner, a solution of 273 grams of CuCl -2H O (1.6 moles) and 70.2 gramsof FeCl -6H O (0.26 mole) in 40 kg. of water in reactor 1 by quickmixing by means of a pump (not shown) was led into the cycle.Approximately equimolar amounts (see the equation in example 5) ofhydrocyanic acid, hydrogen peroxide and hydrochloric acid wereintroduced from the side into the reaction solution through conduits 12,14 and 16. The reaction temperature was held to about 50 C. by coolingwith the help of heat exchanger 7. The crude cyanogen chloride escapingfrom the top of the reactor 1 was freed from the unreacted hydrocyanicacid in washing column 18 as in example 1. The gas composition was thesame as in example 5. To eliminate the water brought in with thehydrochloric acid and hydrogen peroxide in the reaction solution and theWater of reaction per hour 6-7 liters of the catalyst solution were ledinto the stripping column 2 (which was provided with heat exchanger 8)via conduit 34. The catalyst solution was freed from the cyanogenchloride and unreacted hydrocyanic acid in column 2. The oil gases fromthe top of stripping column 2 via conduit 36 which discharged intoconduit 20 were led to Washing column 18 and treated there as in example5. The stripped catalyst solution passed via conduit 38 into container42 (provided with a stirrer) Where it was collected and treated with anequimolar amount of calcium carbonate (based on the total of cupricchloride and ferric chloride) from conduit 58. The precipitation of thedissolved salts tok place here as the basic copper and iron carbonatesand the formed carbon dioxide escaped via conduit 56. The salts were ledby way of conduit 44 into the centrifuge 46 and there separated fromWaste water and arrived via conduit 50 into container 52 (likewiseequipped with a stirrer) for dissolution with hydrochloric acid. Fromthis container the solution was returned to the reactor 1 via conduit54. The hydrochloric acid (2.5 moles of 31% HCl per mole of combinedcopper and iron carbonates) was introduced into container 52 via conduit48 and the carbon dioxide formed in container 52 escaped via conduit56a. The chlorine containing, chiefly hydrochloric acid containing waterwas drawn off likewise via conduit 28 as in example 5 and employed againas in example 5.

In this apparatus per hour there were reacted 0.932 kg. of hydrocyanicacid (34.6 moles) with 4.075 kg. of 31% aqueous hydrochloric acid (34.6moles) and 3.735 kg. of 35% hydrogen peroxide solution (38.45 moles) toform 1.915 kg. of cyanogen chloride, i.e. about of theory (2.13 kg.)calculated on the HCN.

EXAMPLE 7 In the apparatus of FIG. 3 which operated in a continuousmanner, a solution of 400 grams of CuSO 5H O (1.6 moles) and 72.2 gramsof FeSO -7H O (0.26 mole) in 40 kg. of water in reactor 1 by quickmixing by means of a pump (not shown) was led into the cycle.

According to equation III the corresponding amounts of hydrocyanic acid,chlorine gas and hydrogen peroxide (the latter in slight excess) wereintroduced into the reaction solution. The hydrocyanic acid and hydrogenperoxide were introduced to reactor 1 through conduits 12 and 14 as inexamples 5 and 6. The main amount of the chlorine necessary for thereaction passes via conduits 60 and 62 into the upper part of thewashing column 18 and reacts with the hydrogen cyanide dissolved in thereaction solution according to equation I.

The hydrochloric acid formed according to equation I enters the reactor1 where it reacts with hydrogen cyanide and hydrogen peroxide accordingto equation II to form cyanogen chloride. The hydrogen cyanide presentwith this cyanogen chloride after being separated from the catalystsolution in stripping column 2 via conduit 64, enters washing column 18where again with the chlorine it forms hydrochloric acid according toequation I. In this manner the cycle is closed.

Conduit 72, container 66 and conduit 68 only serve the purpose ofremoval of the residual hydrocyanic acid (about 2%) from the departingcyanogen chloride gas by introduction of the residual chlorine (2% ofthe total chlorine) into the head of washing column 18 where it reactswith the hydrocyanic acid to form cyanogen chloride. A portion (50%) ofthe catalyst solution also goes via conduit 70 to container 66.

The reaction temperature in reactor 1 is held at about 50 C. Toeliminate the water brought in with the hydrogen peroxide and thatformed in the reaction per hour about 2 liters of catalyst solution fromreactor 1 were led into the stripping column 2 where it was freed ofdissolved cyanogen chloride and unreacted hydrocyanic acid as in example5. 50% of the catalyst solution was recycled via conduit and the balanceas stated above went via conduit 70 to container 66. The 01f gas fromthe top of stripping column 2 was led via conduit 64 to washing column18. The stripped catalyst solution for recovery of copper and iron saltsand the separation of water was further processed as in example 6 butadding sulfuric acid rather than hydrochloric acid. The calcium sulfateformed was removed in centrifuge 46 and the CuSO and FeSO returned viaconduit 74 to the reactor 1.

In this apparatus per hour there were reacted 0.932 kg. of hydrocyanicacid (34.6 moles) with 1.23 kg. of chlorine gas (17.3 moles) and 1.87kg. of 35% hydrogen peroxide (19.25 moles) to form 1.96 kg. of cyanogenchloride, i.e. about 92% of theory (2.13 kg.) calculated on the HCNemployed.

What is claimed is:

1. A process for the production of cyanogen chloride consistingessentially of reacting (1) hydrogen cyanide with (2) aqueoushydrochloric acid and (3) hydrogen peroxide in the presence of either(a) a water soluble cupric salt as a catalyst in an amount of at least0.05 mole per liter of solution or (b) a water soluble cupric salt in anamount of at least 0.05 mole per liter of solution together with a watersoluble ferric salt as an activator in an amount of at least 0.05 moleper liter of solution.

2. A process according to claim 1 wherein the water soluble ferric saltis present as an activator.

3. A process according to claim 1 wherein the hydrochloric acid is a 3to 36 weight percent aqueous solution of hydrochloric acid.

4. A process according to claim 3 wherein the hydrogen cyanide is addedeither in gaeous or liquid form.

5. A process according to claim 4 wherein the hydrogen peroxide is addedas a 35 weight percent aqueous solution.

6. A process according to claim 4 wherein the cupric salt is cupricchloride.

7. A process according to claim 6 wherein ferric chloride is also addedas a promoter. )1

8. A process according to claim 1 wherein the cupric salt is selectedfrom the group consisting of cupric chloride, cupric cyanide, cupricnitrate, cupric bromide and cupric sulfate.

9. A process according to claim 1 wherein the cupric salt is the salt ofan inorganic acid.

10. A process according to claim 9 including a ferric salt of the sameinorganic acid as the cupric salt.

11. A process according to claim 1 wherein the cupric salt solution isfirst mixed with a ortion of the hydrochloric acid and then the otherreactants are added and finally the remainder of the hydrochloric acidis added.

12. A process according to claim 1 wherein (1), (2) and (3) are used inequimolar amounts.

13. A process according to claim 1 which is carried out continuously.

14. A process according to claim 13 wherein a water soluble ferric saltis also added as an activator.

15. A process according to claim 13 wherein the cyanogen chloridecontaining reaction solution after removal of cyanogen chloride is freedof cupric salt by precipitation with alkali metal or alkaline earthmetal carbonate, the precipitated cupric carbonate is treated withaqueous strong mineral acid to form water soluble cupric salt catalystsolution and the catalyst solution is returned to the reactor forproducing cyanogen chloride.

16. A process according to claim 15 wherein a water soluble ferric saltis also added and the cyanogen chloride containing reaction solutionafter removal of cyanogen chloride is freed of ferric salt byprecipitation with said alkali metal or alkaline earth metal carbonate,the precipitated ferric carbonate is treated with said aqueous strongmineral acid to form water soluble ferric salt in said catalystsolution.

17. A process according to claim 16 wherein the catalyst solution afterremoval of cyanogen chloride is heated to remove a portion of waterpresent by distillation and the concentrated catalyst solution isreturned to the reaction step.

18. A process according to claim 17 wherein half of the hydrogen cyanideis reacted first directly with chlorine to form cyanogen chloride andhydrogen chloride and then the remainder of the hydrogen cyanide isreacted with the hydrogen chloride thus formed and the hydrogen peroxideto form further cyanogen chloride.

19. A process according to claim 13 wherein half of the hydrogen cyanideis reacted first directly with chlorine to form cyanogen chloride andhydrogen chloride and then the remainder of the hydrogen cyanide isreacted with the hydrogen chloride thus formed and the hydrogen peroxideto form further cyanogen chloride.

20. A process according to claim 1 wherein the mole ratios of hydrogenchloride to hydrogen cyanide to hydrogen peroxide are 0.9 to 1.1 molesof hydrogen chloride, 0.9 to 1.1 moles of hydrogen cyanide and 0.9 to

1.1 moles of hydrogen peroxide.

References Cited UNITED STATES PATENTS 999,215 8/1911 Focrsterling 1052,865,708 12/1958 Dinsmore et al. 75108 X FOREIGN PATENTS 1,173,8827/1964 Germany.

OTHER REFERENCES Schumb et al., Hydrogen Peroxide, 1955, pp. 565- 566.

Williams, Cyanogen Compounds, 2nd ed., 1948, pp. 5-9.

Chemical Abstracts, vol. 18, p. 795 (1924).

Groggins, Unit Processes In Organic Synthesis, 5th ed., 1958, pp.507517.

MILTON WEISSMAN, Primary Examiner U.S. Cl. X.R. 42342,

1. A PROCESS FOR THE PRODUCTION OF CYANOGEN CHLORIDE CONSISTINGESSENTIALLY OF REACTING (1) HYDROGEN CYANIDE WITH (2) AQUEOUSHYDROCHLORIC ACID AND (3) HYDROGEN PEROXIDE IN THE PRESENCE OF EITHER(A) A WATER SOLUBLE CUPRIC SALT AS A CATALYST IN AN AMOUNT OF AT LEAST0.05 MOLE PER LITER OF SOLUTION OR (B) A WATER SOLUBLE CUPRIC SALT IN ANAMOUNT OF AT LEAST 0.05 MOLE PER LITER OF SOLUTION TOGETHER WITH A WATERSOLUBLE FERRIC SALT AS AN ACTIVATOR IN AN AMOUNT OF AT LEAST 0.05 MOLEPER LITER OF SOLUTION.